Nortel Networks Circuit Card - Manual (Page 715)

NTAK09 1.5 Mb DTI/PRI card Page 715 of 906
Circuit Card Description and Installation
Architecture
Signaling interface
The signaling interface performs an 8 Kbps signaling for all 24 channels and
interfaces directly to the DS-30X link. Messages in both directions of
transmission are three bytes long.
Interconnection
The interconnection to the carrier is by NTBK04 1.5 Mb carrier cable.
The NTBK04 is twenty feet long. The NT8D97AX, a fifty-foot extension, is
also available.
Microprocessor
The NTAK09 is equipped with bit-slice microprocessors that handle the
following major tasks:
• Task handler: also referred to as an executive, the task handler provides
orderly per-channel task execution to maintain real-time task ordering
constraints.
• Transmit voice: inserts digital pads, manipulates transmit AB bits for
DS1, and provides graceful entry into T-Link data mode when the data
module connected to the DTI/PRI trunk is answering the call.
• Receive voice: inserts digital pads and provides graceful entry into
T-Link data mode when the data module connected to the DTI/PRI trunk
is originating the call.
• T-Link data: a set of transmit and receive vectored subroutines which
provides T-Link protocol conversion to/from the DM-DM protocol.
• Receive ABCD filtering: filters and debounces the receive ABCD bits
and provides change of state information to the system.
• Diagnostics
• Self-test